Strikeforce welterweight champion Nick Diaz didn’t perform up to snuff when he first met K.J. Noons at 160 pounds nearly three years ago.

Now, the champ has an opportunity to right that wrong under better circumstances when he again meets Noons in his second welterweight title defense at “Strikeforce: Diaz vs. Noons II.”

The title fight headlines Saturday’s intriguing event, which airs on Showtime from the HP Pavilion in San Jose, Calif.

For Diaz, it could answer the question of whether he’s a better fighter than Noons when competing in his natural weight class. For Noons, a first-time 170-pounder, it’s a test of how his quickness is affected by additional size and whether he can push Diaz backward in the second go-around.

Noons (10-2 MMA, 2-0 SF) and Diaz (22-7 MMA, 3-0 SF) met in November 2007 in the now-defunct EliteXC organization, and an instant rivalry was born. Noons, a still-green MMA fighter and sometime-professional boxer, turned in a starmaking performance when he shut down Diaz’s ground game and landed hard punches and knees that badly cut his brash opponent.

It was the lightest Diaz had ever been in a fight after serving the bulk of his career at welterweight. Noons, meanwhile, previously had fought in MMA as a lightweight and between 150 and 160 pounds as a boxer.

Doctors ruled the bloodied Diaz unable to continue between the first and second rounds, and Noons became the EliteXC lightweight champion. Diaz refused to acknowledge that he’d been beaten and protested the stoppage.

But Noons’ triumph was short lived when EliteXC stripped him of his lightweight title when he refused a rematch with Diaz. The two subsequently sparred in the press with Diaz on the offensive for the perceived slight.

In the buildup to Saturday’s fight, Noons said he was never opposed to a rematch with Diaz – only to the steep pay cut EliteXC asked him to accept for the bout. Coupled with problems he had with his manager at the time, Noons sawthe fight fall by the wayside, and he subsequently moved back to boxing.

Cut to two years later, and both fighters have made their way to Strikeforce following the collapse of EliteXC. Diaz is riding high as the Strikeforce welterweight champion while Noons is rising fast in the promotion’s lightweight division after putting boxing on the backburner. But Noons is having an increasing difficulty reaching 155 pounds, he said, as the result of his still-growing frame.

Fans clamored for Diaz to fight Jason “Mayhem” Miller, a middleweight whom he brawled with following his teammate Jake Shields’ victory over Dan Henderson at the CBS-televised “Strikeforce: Nashville” event. But with more to lose career-wise at the higher weight, Diaz and Co. had another idea.

At welterweight, Diaz had a chance to avenge a loss.

“I saw the first fight, and it looked to me that Nick looked pretty lethargic,” said Cesar Gracie, Diaz’s trainer and manger. “He just didn’t look good. He didn’t look sharp, and especially when you go down a weight because smaller people are quicker.

“He would throw something out and not bring it back in. He was susceptible to counters, and everything looked a bit off. Since then, he has moved back up in weight, and we have seen a whole different fighter. He is a completely different fighter up at 170.”

Although Diaz claims to have let go the personal animosity he had toward Noons following the first fight, he’s anxious to prove he’s a better fighter this time out.

“I feel good weight-wise,” Diaz said. “I was angry for a long time (about the first fight). I was real upset that it ended the way it did because it wasn’t like I was hurt.

“Then I kind of dropped the idea of ever fighting a rematch because he got out of MMA. I never considered the first fight as a loss. I just always looked at it as a fight that was stopped (too soon).

“I don’t feel that this fight is about revenge. But I’m happy now that he took the fight.”

Noons is fighting at the heaviest mark of his career, though he claims 170 pounds is better suited to his natural weight.

Still, it’s an issue whether he’ll retain his speed on Saturday night – and whether Diaz can wear him down with more energy to burn.

Noons, of course, said he’s still got Diaz’s number.

“Tell Nick to bring my belt,” Noons said. “Same result, different day. Styles make fights. Nick is back on top, I am coming back on top, and I think it makes for an interesting matchup. There is a history there, and it’s perfect timing. I think timing is everything.”

In the first fight, Noons used active footwork to stick straight punches in Diaz’s face and move out of the way when counters arrived. He sprawled when Diaz tried to take the fight down and several times offered a knee when Diaz pitched forward, one one of which caused the damage that set the fight’s end in motion.

Diaz’s usually high punch count was replaced by a slow moving drive to get the fight to the mat, and when he did, Noons popped right back up.

But Noons said he didn’t actually do what he wanted to do.

“The whole camp I trained to come forward and make him fight backward because he never fights backward,” Noons said of the first meeting. “He probably can’t even fight backward. His defense is his offense. So in the first fight I was trying to come forward, and he wasn’t letting that happen, so I couldn’t come forward because I didn’t want to get taken down.”

This time around, you can bet he’ll at least attempt to meet force with force and execute that original plan without over-committing to strikes.

“He is going to want to take me down, wear me down, try to submit me,” Noons said. “He’s going to ground and pound and try to get me tired. My game play is I run up the middle like a football player, so try to stop me. He is not going to come out with some crazy stuff. People pretty much stay with their styles. I am just going to run my play, (so) try to stop it.”

Diaz’s camp believes Noons eventually will tire and succumb to pressure.

“The good thing about Nick is he is a natural right-handed boxer; he just likes to fight southpaw,” Gracie said. “It is going to be a long fight, and Nick is pretty relentless.”

Similar to Noons and Diaz’s meeting, this women’s bout is a weighty matter for Coenen. It’s the first time she’s fought at 135 pounds after having spent the majority of her career at 145 pounds.

As Kaufman recently told MMAjunkie.com (www.mmajunkie.com), that could be a big problem if the fight goes into later rounds. If Coenen is lean at 145 pounds, she could be drained at 135.

And against Kaufman, a fighter after Diaz’s heart in terms of the relentless pressure she applies to opponents, Coenen will need to make a strong statement early on.

But that’s not necessary, according to the Dutch fighter.

“I’m good on my weight and feel strong,” Coenen said. “That helps my confidence a lot (in) fighting at 135 pounds. Coming down from 145 was a gradual process, but I had a good nutritionist and team working with me. I don’t think I’ve lost any strength, but I definitely feel faster.”

Coenen will need that speed to stay out of the way of Kaufman’s bulldozing attack. As in Noons’ first fight with Diaz, a hit-and-run attack will keep the champion at bay and prevent takedowns.

If the action hits the ground, Coenen’s best bet is to throw up a triangle or armbar as Kaufman is attempting to work ground and pound.

Kaufman, of course, will storm forward and try to wear down Coenen. A longer fight will show fans whether Coenen is truly suited for the women’s welterweight class.

In other main card action, former Stikeforce lightweight champion Josh Thomson (17-3 MMA, 8-2 SF) battles American Top Team standout Gesias “JZ” Cavalcante (15-3-1 MMA, 0-0 SF) in a bout to determine the next challenger to current title-holder Gilbert Melendez. The winner also could re-emerge in the top-10 rankings for the lightweight division.

Unbeaten welterweight prospect and NCAA Division I All-American wrestler Tyron Woodley (6-0 MMA, 4-0 SF) also takes on submission specialist Andre Galvao (5-1 MMA, 2-0 SF). The winner could be on the fast track to a future title shot.

As the UFC 189 tour made its last stop in Dublin, featherweight champ Jose Aldo was met with a torrent of abuse from the Irish fans. It might have been unpleasant, but it might also have been just what he needed.